I am going to start glutamine synthetase gene amplification to overexpress a protein in CHO-K1 cells. I have noticed that some papers have used the GS minigene and the others employed GS cDNA. I was wonedring which sequence is more efficient for amplification and i also cant find the exact sequence for the GS minigene. although the minigene has been used in pEE14 expression vectors but I dont have access to the sequence. I reaaly appreciate any suggestion.